Perioperative complications at scale: a multi-center analysis of 1.2 million surgical inpatients and the ethical imperative for risk transparency

Background Major inpatient surgery is associated with significant postoperative morbidity, yet large-scale contemporary data characterizing complication patterns remain limited. Understanding complication epidemiology is essential for individualized risk assessment and shared decision-making. This study aimed to validate prior findings of perioperative complication rates and characterize complication patterns by type, timing, surgical service, patient demographics, and the COVID-19 pandemic period. Methods We developed a tool in early 2019 to prospectively collect perioperative outcomes for patients undergoing major inpatient surgery across 35 different medical centers. We analyzed data from 1,214,539 surgical inpatients receiving care between October 2017 and December 2023. Complications were time stamped and identified using ICD-10 codes, and categorized as pulmonary, cardiac, renal, neurologic, hemorrhagic, or septic. Complication proportions were stratified by surgical service line, postoperative day, age, sex, and American Society of Anesthesiologists physical status. Results The overall complication rate was 7.6% (range 0.52%-23.72% by service line). Cardiac surgery (23.72%), ECMO (20.31%), and neurosurgery (19.89%) had the highest complication rates. The most frequent complications within 7 days per 1000 patients were: postoperative pulmonary complications (6.41), acute kidney injury (5.36), postsurgical sepsis (4.64), acute coronary syndrome (1.00), stroke (0.69), and cardiac arrest (0.63). Complications increased with age (0.67% ages 0–10 years to 15.65% ages 91–100) and were higher in males (9.20%) than females (6.46%). Post-pandemic complication rates (7.68%) declined below pre-pandemic levels (8.32%) and were highest during the emergency surgery only phase of the pandemic (10.53%). Complication rates ranged from a facility-level low of 0.96% to a high of 15.98%, while at the procedure level (CPT codes), certain low-volume interventions had 100% complication rates. Conclusions Complications following major inpatient surgery occur in up to 1 in 4 patients in high-risk surgical populations, and vary significantly by institution and procedure. Surgical facilities should utilize similar methodologies to define their own outcomes to drive perioperative quality improvement. Furthermore, patients have a fundamental right to know these data before consenting to surgery. Institutional complication rates should be made publicly available to facilitate shared decision-making and informed consent.